Fluid pressure multiple clutch control equipment



Patented May 27, 17952 FLUID PRESSURE MULTIPLE CLUTCH CONTROL EQUIPMENT Roy R. Stevens, Forest Hills, Pa., assigner to Westinghouse Air Brake Company, a corporation of Pennsylvania Application August 12, 1949, Serial No. 109,925

(Cl. (S-97) 9 Claims.

This invention relates to control apparatus and more particularly to means for controlling the selective operation of a plurality of devices such as clutches.

The principal object of the invention is the provision of improved control apparatus for controlling the selective operation of two positive type clutches arranged to be driven through an impositive type clutch, in such manner as will prevent engagement of either of the positive type clutches when the impositive type clutch is engaged so as to prevent damage to the positive type clutches.

Other objects and advantages will be apparent from the following more detailed description of the invention.

In the accompanying drawings; Fig. 1 is a diagrammatic view, partly in outline and partly in section, of control apparatus embodying the invention associated with a clutch system; and Fig. 2 is a schematic sectional view of a relay valve devi-ce,rseveral of which are shown in outline in Fig. 1 as comprised in the control apparatus.

Description The improved control apparatus is shown in the drawing associated with a fluid pressure clutch system for sake of illustrating utility of the invention.

The clutch system may comprise a main friction clutch I having a driving element 2 journaled onto an input shaft 3 and attached to a sprocket wheel il which may be driven through the medium of a chain 5 by suitable power means (not shown). A driven element 6 is secured for rotation with the input shaft 3 and is slidable axially thereon into and out of frictional contact with the driving element 2 for engaging and disengaging, respectively, the friction clutch I to establish and disestablish, respectively, driving connection between the power means and the input shaft 3. The input shaft 3 in turn may be operatively connected to a jaw clutch driving shaft 8 through the medium of sprocket wheels 9, I0 and a chain II so that shafts 3 and 8 simultaneously either will be driven or not driven by the power means according to engagement or disengagement, respectively, of the friction clutch I. The shaft 8 in turn is operatively connected to two driving elements 9 and I0 of two jaw clutches Il and l2, respectively, through the medium of sprocket wheels I3 and I4 secured to rotate with the shaft 8, chains I5 and I6. and sprocket wheels I1 and I8 attached to the driving elements 9 and I8', respectively. Attached sprocket wheels Il and I8 and driving elements 9 and IIJ are journaled on an output shaft 20 so that same will be driven by the power means along with shafts 3 and 8 when the friction clutch I is engaged and will not bev so driven when the clutch I is disengaged. A driven element 2| common to both of the jaw clutches II and I2 is slidably mounted for axial movement along shaft 26 into and out of meshing engagement with the driving elements 9' and l. The driven element 2l is operatively connected to the output shaft 20 by such means as a key (not shown) so that when the element ZI is in meshing engagement with either of the driving elements 9 or I, that is when either of the jaw clutches II or I2 is engaged, and when the friction clutch I is engaged, a driving connection is established from the output shaft 28 through shafts 3 and 8 to the power means. With either the friction clutch I disengaged or both jaw clutches II and I2 disengaged, driving connection between the power means and the output shaft 20 will be disestablished. It will also be seen that driving connection between the output shaft 20 and the jaw clutch input shaft 8 will be disestablished when both jaw clutches I I and I2 are disengaged and established when either is engaged. The output shaft 20 is adapted through provision of a sprocket wheel 23 and chain 24 to be operatively connected to a device to be driven (not shown). The ratio of diameters of the sprocket wheel combinations I3, Il and I4, I8 may be such as will afford two different operating speeds of the output shaft 2G to give two different speeds of operation of the device to be driven, thereby supporting practical utility of the clutch system with which the control apparatus embodying the invention is associated for controlling operation of same.

The improved control apparatus embodying the invention comprises a luid pressure friction clutch actuator 30 operatively connected to the driven element 6 through the medium of a clevis 29 slidably disposed in the usual fashion within a peripheral annular groove formed in said element for moving same into and out of engagement with the driving element 2 for thereby engaging and disengaging the friction clutch I. The clutch actuator 36, forsake of illustration, schematically may simply comprise a cylindrical casing in which is slidably disposeda piston 3| operatively connected by means of a piston rod 32 and link 33 to a pivoted clevis arm 34.` Upon assenze supply of fluid under pressure to a pressure chamber 55 at one side of the piston SI same will be caused to move against action of a return spring 36 in a non-pressure chamber at its opposite side to engage the friction clutch I through movement of the clevis arm 34 about a fixed pivot pin 3S. Upon release of uid under pressure from the chamber 35, the spring 35 will return the piston 3l to the position in which it is shown in the drawing in contact with a shoulder formed in an end wall of the casing, thereby causing the friction clutch i to be disengaged, as it is shown in the drawing.

For controlling supply and release of ii-uid under pressure to and from the pressure chamber 35 in the actuator 3G, and therefore engagement and disengagement of the friction clutch I, a friction clutch control device 4B is provided. The friction clutch control valve device @e may be of any suitable structure, such, for example, as r the type disclosed in Patent No. 2,329,742, issued to Rankin J. Bush et al. on September 2l, 1943, to which may be connected two control pipes 42, i3 and a huid pressure supply pipe it and which comprises an operators handle d movable from a neutral position, in which it is shown in the drawing with both control pipes t2, t3 vented, to either of two, positions at opposite sides of neutral to effect Supply of fluid under pressure from the supply pipe 44 to one or the other of the control pipes. As the device 4D is employed in the present apparatus, the control pipe 42 is connect ed atits opposite end to the pressure chamber in the friction clutch actuator 39, the control pipe d3 may be blanked off since there is no need for same, and the supply pipe 44 may be connected to a fluid pressure supply reservoir Ill which may be kept supplied with a suitable volume of fluid under pressure from such as a huid compressor (not shown) to furnish a source of working duid for the control apparatus. Only two positions of the handle llmay be considered for controlling operation of the friction clutch I, the neutral position in which it is shown in the drawing and indicated by a dot-and-dash line titled friction clutch disengaged and in which the control pipe Q2, hence chamber 35 in actuator 3b, is vented, with the friction clutch I consequently disengaged, and one position out of neutral indicated by a dot-and-dash line titled friction clutch engage@ in which position the control pipe t2, hence the pressure chamber 35, will be charged with fluid under pressure and in which the friction clutch I consequently will be engaged.

The control apparatus further comprises a jaw clutch actuator 50 for effecting engagement and disengagement of the jaw clutches selectively. The actuator 5i! may comprise a cylindrical casing having a piston `5I slidably disposed therein which is operatively connected to the driven element ZI of the jaw clutches I I, I2 through the medium of a clevis 52, an` attached pivotal arm 53, a link 5i and a piston rod 55. Return springs and 5'? disposed in pressure chambers 58 and 58, respectively, at opposite sides of the piston 5I urge the piston toward a neutral position in which it is shown in the drawing and in which both of the jaw clutches II, I2 are disengaged, with the driven element `ZI out of meshing engagement with the driving elements 9' and I0. Upon supply of iiuid under pressure to the chamber 58, with the chamber 59 vented, resultant movement of the piston 5I willv cause engagement of the jaw clutch II, while subsequent venting of both chambers '58 and 59 will effect return of the piston 5i to its neutral position in which both of the jaw clutches I I and I2 are disengaged. Conversely, upon supply of fluid under pressure to the chamber 59 while chamber -58 remains vented, resultant movement of the piston 5I will cause engagement of the jaw clutch I2 through rocking movement of the clevis arm 5.3 about a xed pivot pin 5t. Upon subsequent venting of both chambers 53 and 59 to atmosphere, the piston 5I will be returned to its neutral position with both jaw clutches II and I2 consequently disengaged.

For controlling operation of the actuator 50 and thereby the jaw clutches II and I2 an operators control device 65, which may be similar to the operators -control device 40, is provided.

The control device 65 is connected to a fluid pressure supply pipe 6l and to control pipes 68 and 69 which in turn are connected to chambers 53 and 59, respectively, in the actuator 59. An operators handle 55 of the control valve device 65 is movable to any one of three positions indicated in the `drawing by dot-and-dash lines titled jaw clutches disengaged, jaw clutch II engaged and jaw clutch I2 engaged, respectively'. In jaw clutch I l engaged position of handle 55, the control pipe 58 will bev connected t0 thel supply pipe El,v while the control pipe 89 will be connected to an atmospheric port 'I in the casing of the valve device. In jaw clutch I2 engaged position of the handle-55 the control pipe ($9 will be connected to the supply pipe 51 while the control pipe 58 will be connected to the atmospheric port lil. In jaw clutches disengaged position of the handle 56, both of the control pipes 58 and G9 will be connected to the atmospheric port 1.0.

According to a feature of the invention, a relay valve device 'II is provided which is operable to establish communication between the supply pipe 'i and either the fluid pressure supply pipe 44,

' hence reservoir 47, or an exhaust pipe l2 which is constantly open to atmosphere. When a communication I I8, indicated in the drawing symbolically by a solid line appearing within the generalV v outline of the relay valve device, is established 'between supply pipes 61 and 44, iiuid under pressure from the supplyV reservoir Ill is available to the control valve device 6 5 for supply to; one or the other of chambers 58, 59 in actuator 5,0 when operators handle 56 is moved to either ofY its clutch engaging positions toestablish -connection -between one or the other pipes 68, 69, respectively, and said supply pipe 51, One or the other jaw clutches I I, I2 will thus -be engaged according to.

which chamber, 58A or 59, in actuator 5B becomes charged in above manner. If, conversely, a communication H9, indicated symbolically inthe drawing by a dash line appearing within the general outline of the valve device 1I, is established, the supply pipe $14 becomes disconnected from the supply pipe 44 and becomes connected to the exhaust pipe 12, whereupon fluidy under pressure` from whichever of the chambers 58, 59 in actuator 50 was charged' at the time will release to atmosphere by way of the respective control pipe 68 or 69, the control valve device 65, thel supply pipe El, communication H9 in relay valve device 'll and the exhaust pipe 12, thereby effecting disengagement of the respective jaw vclutch I I. or I2.

which had been engaged at the time. It will be appreciated that when communication IIS in relay valve device 'II is established movement of the operators handle 56 of control valve device 65 to either of its clutch engaging positionswill .not eiect engagement of jaw clutches l I, Izsince no uid under pressure can be supplied to either of the control pipes 68, 69 with pipe 61 vented to atmosphere via said communication I I9. If, however, were communication IIB to be reestablished when operators handle 66 of the control valve device 95 is in either of its clutch engaging positions, fluid under pressure would ilow from the pipe 49, said communication IIB, the pipe 91, the device 95, and the respective control pipe l98 or B9, to the respective chamber 58 or 59 in the actuator 59 to cause reengagement of the respective jaw clutch II or I2 according to whichever of the clutch engaging positions the operators handle 69 was allowed to remain in.

Referring to Fig. 2 schematically, in detail the type of relay valve device which may be employed as the relay valve device 'II and a relay valve device |25, the function of which will be set forth hereinafter, may comprise a casing |99 having a diaphragm I9| disposed therein and subject to pressure of fluid in a diaphragm control chamber |92 at its one side and to pressure of fluid in a chamber |93 at its opposite side. Also formed in the casing are chambers |99, |95 and |95, chamber |94 being separated from the chamber |93 by a partition |91 and from the chamber |95 by a partition |98. A partition |99 separates the chamber |95 from the chamber |99. A valve ||9 is disposed in the chamber |94 for controlling communication between the chamber |95 and said chamber |94. The valve ||9 may be secured to a fluted stem I|| slidably mounted in a suitable bore extending through the partition |98, a valve seat being formed at the end of the bore opening into the chamber |94 to accommodate the valve IIB. A valve II2, similar to the valve I9, is disposed in the chamber |99 for controlling communication between the chamber |95 and said chamber |99. The valve ||2 is attached to a uted stem |I3 which is slidably disposed in 'a suitable bore extending through the partition |99, a valve seat being formed in the end of said bore openinginto the chamber |99 to accommodate the valve II2. Both of the fluted stems |I| and ||3 project into and meet in the chamber |95. A bias spring ||4 is disposed in the chamber |99 yand arranged to urge the valve ||2 towards its seat and at the same time, through engagementI of stems IIIand 3, to urge the valve II9 away from its seat. The valve ||9 is operably connected to the diaphragm I9I by means of a rod or stem ||5 which extends through a bore in the partition |791. A control spring IIIi is provided in the chamber |93 to oppose deflection of the diaphragm |9| in the direction of -the chamber |93.

In operation of the relay valve device shown in Fig. 2, with the chamber |93 open to atmosphere, upon supply of uid under pressure to the control chamber |92, the diaphragm I9| will deflect in the direction of the chamber |93 against opposition of the control spring IIS and the bias spring H9 and will cause seating of the valve ||9 and unseating of the valve ||2. With the valve I|9 closed and Valve II2 open, chamber |95 will be closed to the chamber |94 and open to the chamber |96. Upon subsequent venting of iluid under pressure from the control chamber |92, the bias spring I|4 and the control spring H9 will return the diaphragm |9| and valves I I9 and I2 to the positions in which they are shown in the drawing, the Valve II2 being seated and the valve |I9 being unseated. With valve ||9 unseated and the valve ||2 seated, the

becomes the case where the device of Fig. 2 is employed as the relay valve deviceI25, it will be seen that the eiect of pressure of fluid in chamber |92 acting on one face of the diaphragm |9| will be nullied by the equal eiect of pressure of fluid in chamber |93 actingon the opposite face of the .'diaphragm, so that same will not be deflected by such supply of fluid under pressure to chamber |92 with chamber |93 thus charged and the valves II9 and II2 will remain unseated and seated, respectively. If while the control chamber ,|92 and the chamber |93 are charged with fluid under pressure, said chamber |93 is vented to atmosphere, iluid under pressure will release therefrom and will allow the pressure of fluid in Athe control chamber to deilect the diaphragm and .seat the valve I|9 while simultaneously unseating the valve I|2. If, on 'the other hand, when the vcontrol chamber |92 is charged with iiuid under pressure, and the diaphragm |9I is deflected thereby with chamber |93 vented to atmosphere, uid under pressure is supplied tothe chamber I93pressure forces on opposite faces. of the diaphragm will again be balanced, and the springs ||4 and II 6 will return the diaphragm and valves II9 and ||2 to the positions in which they are shown in the drawing, that is, vunseated and,V seated, respectively.

In describing operation of the relay valve devices |25 in the apparatus shown in outline in Fig. 1 which are similar to the device shown in detail in Fig. 2, the communication I I8, shown symbolically by the solid line in Fig. 1, will imply that connection which is either established or disestablished between the chambers |94 and |95 according to whether the valve II9 is seated or unseated, respectively, and the communication |I9, shown symbolically by the dash line in Fig. l, will imply that connection which is either established or disestablished between the chambers |99 ,and |09 according to whether the valve ||2 is seated or unseated, respectively.

In the relay valve device '|I, its chamber |93 is constantly open to atmosphere by way of such as a port I2I, its chamber |94 is connected to the supply pipe 44, its chamber |95 is connected to the supply pipe 61, and its chamber |99 is connected to the exhaust pipe I2 constantly open to atmosphere.

For controlling supply and release of fluid under pressure to and from the control chamber |92 in the relay valve device '|I, hence for controlling operation of said device '|I, `the previously mentioned relay valve device |25 is provided which is similar in structure and operation to the previously described relay valve device shown in detail in Fig. 2. In the relay valve device |25, its chamber |94 has a connection with the control pipe 42 by way of a pipe |26 and a check valve I2? and choke |29 arranged in parallel and with a volume reservoir |29', for reasons which will be set forth hereinafter. Also in relay valve device |25, its chamber |95 is connected to the control chamber |92 in the relay valve device II by way of a pipe |29; its chamber |96 is connectedto an exhaust pipe |39 which is constantly open to atmosphere; its Vcontrol chamber |92 is connected by way of a pipe |3| to an outlet opening |32' of va shuttle, valve device I l33, opposite inlet openings I 34, of which are .connected to the control pipes |58 and 69, respectively; and its chamber |93v is connected by way of .a pipe |36 to an outlet chamber 325 oi an inverse double check valve device |29. opposite inlet chambers of which are connected to the control pipes `68, 69, respectively, as will be described subsequently.

The inverse double check valve device |46 schematically may comprise a casing 323 having a bushing 324 which is encircled midway between its ends by the chamber 325 connected to the pipe |36. The bushing 324 is provided interiorly and midway between its ends with a bridge having an axial bore 325 open to the chamber 325 through a plurality of radial openings 321 At opposite ends of the bore 326 are annular seats arranged for sealing engagement by respective valves 328, 329 contained in chambers 330, 33|, respectively. The two valves 328 and 329 are connected for movement in unison by a stem 332 extending with clearance through the bore 326. This stem is of such construction as will allow flow of duid under pressure past either valve 328 or 329, when unseated, through the bore 326 to the annular chamber 325. The chamber 330 is connected to the control pipe 6B and the chamber 33| is connected to the control pipe xE9.

In operation of the inverse double check valve device |43, when only one of the pipes B8, 69 is charged with fluid under pressure, the respective valve 328 or 329 will close to prevent fluid under pressure from flowing into the pipe |36 to chamber |33 in the relay valve device |25, while the pipe |36 remains vented by way of the other unseated valve 328 or 329 and the respective uncharged control pipe 69 or 59. When both of the pipes 68 and 69 become charged with :duid under pressure, fluid under pressure will flow from one or the other of these pipes by way of whichever of the valves 328, 329 is unseated, into the pipe |33 to the chamber Ill-3 in the relay valve device |25.

Operation In operation of the control apparatus, assume that the reservoir 4T is charged with fluid under pressure and that the respective operators handles of the control valve devices and 55 are in their respective neutral positions in which they are shown in the drawing with the control pipes 2, 58, and S9 vented to atmosphere. All clutches I, I| and I2 will be disengaged. The control chamber |2 in the relay valve device |25 will be void of fluid under pressure with same vented to atmosphere by way of the shuttle valve device l |33 and one or the other of the control pipes 68, 39. The chamber I3 in the relay valve device |25 will be void of fluid under pressure with same vented to atmosphere by way of the inverse double check valve device IAD and one or lthe other of the control pipes 58, 69. With its control -chamber |22 thus void of fluid under pressure, the relay valve device |25 will be in its position establishing the communication H8 which connects the pipe |26 to the pipe |29 so that the control chamber |02 in the relay lvalve device 'II will be vented to atmosphere at this time by Vway of the pipe |29, said communication IIS, the pipe |26 and choke |28 therein, and the control pipe 22. The relay valve device 'II thus will be so conditioned as to maintain its communication I8 established, connecting the supply pipe |61 to the supply pipe 44 so that fluid under pressure from the reservoirA'I will be yavailable to the operators control device via said communication IIS.

Assume now that through operation of the control valve device 40 fluid under pressure is supplied to the control pipe 42 for effecting engagement of the friction clutch I as will be appreciated from previous description. Such fluid under pressure thus supplied to the control pipe 42 will flow by way of the pipe |26 and the check valve |21 to the volume reservoir |29' and by way of the communication I|8 in the relay valve device |25 and the pipe |29 to the control chamber in the relay valve device 1|. The relay valve device 7| will then respond to disestablish its communication IIS which connects pipe 6l with pipe 45| and to establish its Comunication I I9 which connects the pipe 6l to the exhaust pipe 'I2 so that no supply of fluid under pressure will be available to the jaw clutch control valve device 65. Neither of the jaw clutches I I or I2 may then be engaged through operation of the valve device 65 with the driving connection through the engaged friction clutch in existence, therefore precluding damage to the jaw clutches were same to be engaged with their driving elements 9', I9 rotated through said engaged friction clutch.

Upon subsequent venting of the control pipe 42 by operation of the friction clutch control valve device dll, iiuid under pressure will release slowly from the control chamber in the relay valve device 'II by way of communication |18 in the relay valve device |25, the pipe |26 and choke |28 therein and the control pipe 42. The relay valve device 'II will then respond to reestablish its communication IIB for allowing supply of uid from reservoir 41 to reach the jawclutch control valve device 65 via pipe 61 so that either of the jaw clutches II or I2 may then be engaged through effecting supply of iluid under pressure to the respective control pipe 68 or G9. The choke |28 so times the above described release of fluid under pressure from the control chamber |02 in the relay valve device 1| as to allow the jaw clutch input shaft 8 to come to rest upon disengagement of the friction clutch I before the jaw clutch control valve device |55 is rendered elective to engage either of the jaw clutches.

Now assume that with the control pipe I2 vented and the friction clutch I therefore disengaged, fluid under pressure is supplied to one or the other of the control pipes 68 or 69 to cause engagement of a respective jaw clutch or I2. Such fluid under pressure will ow from the charged control pipe B8 or 69 by way of the shuttle valve device |33 and the pipe |3| to the control chamber |02 in the relay valve device |25. The chamber |03 in the relay valve device |25 will remain vented at this time b-y way of the pipe |36, the inverse double check valve device |4|l and the vented one of the control pipes E3 or 69, as will be appreciated from previous description. The relay valve device |25 will then respond to disestablish its communication IIB which connects pipe |29 to the pipe |26 and establish its communication |I9 which connects the pipe |29 to the exhaust pipe |39, hence to atmosphere. The status of the relay valve device 1| will remain the same at this time with its communication II8 established and connecting the pipe |51 to the pipe 44 so that the respective control pipe 68 or B9 will remain charged with iiuid under pressure from reservoir 4l via control valve device 65 and the respective jaw clutch I| or I2 will remain engaged.

Now the friction clutch I may be engaged through supply of fluid under pressure to the control pipe 42 by operation of the control valve device 40 while the respective jaw clutch II or I2 remains engaged to establish driving connection between the power input shaft 3 and the power output shaft 2|). Such uid under pressure will flow from the control pipe 42 by way of the pipe |26 and check valve |2'I to the volume reservoir |29' which thereby becomes charged for reasons which will hereinafter become apparent. Fluid under pressure thus supplied to the pipe |26 at this time will be prevented from reaching the control chamber |02 of the relay valve device II by the relay valve device |25 which will remain positioned with its communication II8 disestablished and its communication II9 established thereby maintaining pipe |29, hence said control chamber, vented to atmosphere via pipe |30. The respective control pipe 68 or 69 will remain charged with fluid under pressure by virtue of connection with reservoir 41 by way of the control valve device 65, pipe B7, communication II8 in relay valve device '|I, and the pipe 44 so that it will be seen that the respective jaw clutch II or I2 will remain engaged when the friction clutch I is subsequently engaged.

Now assume that with one of the jaw clutches, II or I2 and the friction clutch I engaged it is desired to disengage that particular jaw clutch and to engage the other of the jaw clutches, II or I2. If such is accomplished by moving the operators handle 66 from its one jaw clutch engaging position first to its neutral position and then after a pause to its otherl jaw clutch engaging position, both control pipes 68 and 69 will be connected to the exhaust port 'III in the neutral position of the handle 66 while fluid under pressure releases from clutch actuator 5I) by Way of the respective control pipe v|58 or 69 and the port 'I0 in control valve device S5 to disengage the previously engaged jaw clutch II or I 2. With sufficient pause before moving the operators handle from its neutral position 66 to its other jaw clutch engaging position, fluid under pressure will also release from the control chamber in the relay valve device |25 by way of the pipe ISI, shuttle valve device |33 and one or the other of the two vented control pipes 68, 69 to allow the relay valve device |25 to reestablish its communication II3. Upon such establishment of communication I I 8 in relay valve device |25 uid under pressure will flow from the control pipe 42 and from the volume reservoir |29' by way of pipe |26, said communication, and the pipe |22 to the control chamber in the relay valve device 'II which will respond theretoto disestablish its communication I|8 which connects pipe 6l with pipe 44 and to establish its communication IIe which vents the supply pipe B1 to atmosphere by way of exhaust pipe 72. When the operators handle 66 is then moved from its neutral position to the desiredl clutch engaging position, the respective control pipe 68 or 69 will be connected through the control device 65 to the vented supply pipe E'I so that both jaw clutches II and I2 will remain disengaged.

With the operators handle 65 thus in a clutch engaging position and the supply pipe I5'I vented via relay valve device II so that both jaw clutches II and I2 are disengaged, the friction clutch I may be disengaged to allow for the desired engagement of the respective jaw clutch through venting of the control pipe 42 by operation of the valve device 4I). Such venting of the control pipe 42 will allow slow release of fluid under pressure from the control chamber in the relay valve device 'II by way of communication I I8 in the relay valve device |25, pipe |26 and the choke |28 while the jaw clutch input shaft 8 slows down to a stop upon disengagement of the friction clutch I. When release of fluid under pressure from the control chamber in the relay valve device 'II is substantially complete, the communication IIB in said device will be established to connect the supply pipe G'I to the pipe 44, whereupon fluid under pressure will flow by way of the control valve device 65 to the respective control pipe 62 or t9 to cause engagement of the respective jaw clutch II or I2, it being assumed that handle 66 of device 65 is allowed to remain in a jaw clutch engaging position.

Such fluid under pressure thus supplied to the respective control pipe 58 or 69 will flow by way of the shuttle valve device |33 and the pipe ISI to the control chamber in the relay valve device |25, causing same to disestablish its communication I I3 and to establish its communication II9 which vents the pipe |29 hence the control chamber in relay valve device 1I, to atmosphere via exhaust pipe |30. The friction clutch I may then be engaged through supply of fluid under pressure to the control pipe 42 and such fluid under pressure will flow by way of the pipe I 26 and check valve |2'I to the volume reservoir |29 to charge same, but will be prevented by relay valve device |25 from flowing to the control chamber in the relay valve device `II which will therefore remain positioned to maintain the supply pipe 6l connected to the pipe 44, hence reservoir 47, so that the respective control pipe 62 or E9 will be maintained charged and the respective jaw clutch II or I2 therefore will remain engaged along with the friction clutch I.

Now assume that, with the friction clutch I and a respective jaw clutch II or I2 engaged and with the relay valve devices positioned establishing their communications IIQ and IIB respectively, the operators handle B of the jaw clutch control valve device 65 is moved directly and rapidly from its one jaw clutch engaging position to its opposite jaw clutch engaging position without pause in its neutral position for shifting from one jaw clutch II or I2 to the other jaw clutch II or I2. vSuch operation of the control valve device 65 will quickly disconnect one of the control pipes 68 or 69, from the supply pipe 6T and connect same to the exhaust port 'III and will connect the other of the control pipes 58 or $9, to the vsupply pipe 5I so that fluid under pressure will flow from the pipe BI into the other control pipe 68 or 69 before fluid under pressure releases from the first control pipe 68 or 69. It will be seen that under such circumstances the control chamber in the relay valve device |25 will be maintained charged with uid under pressure by way of the shuttle valve device |33 and one or the other of the control pipes S8 or 69 so that the relay device |25 would tend to remain positioned venting the control chamber in relay valve .device 'II to atmosphere and therefore preventing venting of the supply pipe BI to atmosphere to prevent engagement of the other jaw clutch I I or I2 while the friction clutch I is yet engaged. To insure that such jaw clutch engagement will not occur when shifting handle 56 rapidly from one jaw clutch engaging position to the other with the friction clutch I engaged, in accordance with a feature of the invention, if both of the control pipes E58 and S9 become charged with iiuid under pressure under the above circum- 11- stances, such fluid under pressure will' flow by way of the inverse double check valve device- 141) and the pipe 136 to the chamber 1113 in the relay valve device 125 to nullify effect of pressure in the control chamber therein, whereupon sai'd relay valve device 125 will respond to disestablish its communication |19 and establish its communication 118. Fluid under pressure from the volume reservoir |29 will then flow rapidly by wayof the communication 11B in relay valve device 125 to the control chamber in the relay valve device '11, causing same to effect theV desired venting of the supply pipe 61 by establishment of the respective communication |19 and prevent engagement of the other jaw clutch 11 or 12 while the friction clutch I is engaged. With the pipe 61 thus vented, it will be appreciated that both control pipes B8 or 69 will become so vented and that fluid under pressure will therefore release from both the control f 125 will remain in its position connecting the pipe 12S, hence the control chamber in relay valve device 11, to the pipe 125, hence to the charged control pipe 42. When the control pipe 42 is vented by operation of the control valve device lil to eilect disengagement of the friction clutch 1, fluid under pressure will release slowly from the control chamber in the relay valve device '11 by way of the relay valve device 125, choke 128 and the pipe 12. When the release of fluid under pressure from the control chamber in y the relay valve device l1 is complete, which, due to action of choke 128, will occur only after the jaw clutch input shaft 8 comes to rest, said relay valve device will again respond to effect supply of fluid under pressure to the supply pipe 61 and via valve device S5 to the respective control pipe 68 or 69 to cause engagement of the respective jaw clutch in accord with position of the operators handle 66.

Upon supply of fluid under pressure to the respective control pipe 63 or 69, such fluid under pressure, as aforedescribed, will flow by way of the shuttle valve device 133 to the relay valve device 125 to cause same to again disconnect the control chamber of relay valve device '11 from the control pipe 42 and to vent said control chamber to atmosphere. The friction clutch I may then be reengaged through supply of fluid under pressure to the control pipe 42 and such fluid under pressure will flow via check valve 12'1 Summary It will now be seen that I have provided iinproved control apparatus for controlling the selective operation of two positive type clutches, arranged to be driven through an impositive type clutch, in such a manner as prevents engagement of either of the positive type clutches when the 12 impositive type clutch is engaged, thereby precluding damage to the positive type clutches which otherwise might occur were same to be engaged while their input elements were beingr drivenl by the impositive type clutch.

Having* now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A control system for one fluid pressure actuator and a pair of fluid pressure actuators selectively cooperative with said one actuator comprising, a conduit for conveying fluid under pressure to said one actuator to effect operation, thereof, two control pipes one for each of said pair of fluid pressure actuators, a fluid pressure supply pipe, an operators control device for selectively establishing a fluid pressure communication between said supply pipe and either one of said two control pipes while opening the 'other of said two pipes to atmosphere, a source of fluid under pressure, valve mea-ns comprising a control element operative by fluid under pressure to vent said fluid pressure supply pipe and upon release of fluid under pressure to open said fluid pressure supply pipe to said source, other valve means responsive to fluid under pressure in one chamber to open said control element to said conduit and to fluid under pressure in another chamber when said one chamber is vented to open said control element to atmosphere, valve means subject opposingly topressures in said two control pipes for selectively opening said one chamber to the one of said pipes at lower pressure, and other valve means also subject opposingly to pressures in said two pipes for selectively opening said other chamber to the one of said two pipes at higher pressure.

2. A control system for a fluid pressure actuator and a pair of fluid pressure actuators selectively cooperative with said actuator comprising, a conduit for conveying fluid under pressure to said actuator, two control pipes one for each of said pair of fluid pressure actuators, a fluid pressure supply pipe, an operators control device for selectively establishing a fluid pressure communication between said supply pipe and either one of said two control pipes while opening the other of said two pipes to atmosphere, a source of fluid under pressure, valve means cooperative with said conduit when supplied with fluid under pressure to supply fluid under pressure to said fluid pressure supply pipe in response to pressure 0f fluid in one chamber and to vent said fluid pressure supply pipe in response to subsequent supply of fluid under pressure to a second chamber, and means controlled by opposing pressures in said pipes for selectively opening said one chamber to the one of said two pipes at higher pressure and said other chamber to the one of said two pipes at lower pressure.

3. A control system for one fluid pressure actuator and a pair of fluid pressure actuators selectively cooperative with said one fluid pressure actuator comprising, control means for selectively effecting operation of each of said actuators, and means operative when said one fluid pressure actuator is operated to prevent operation of either of said pair of fluid pressure actuators upon operation of said control means to effect termination of operation of either of said pair of fluid pressure actuators and operation of the other.

n 4. A control system for a power transmission including one fluid pressure actuator and a pair of fluid pressure actuators selectively cooperative with said one fluid pressure actuator comprising,

control means for selectively effecting operation of each of said pair of uid pressure actuators, and means operative when said one uid pressure actuator is in operation to prevent operation of either of said pair of fluid pressure actuators and operative in response to operation of said control means to effect termination of operation of said one fluid pressure actuator to effect operation of the selected one of the pair of actuators.

5. A control system for one fluid pressure actuator and a pair of fluid pressure actuators selectively cooperative with said one fluid pressure actuator comprising, a first control means for controlling operation of said one fluid pressure actuator, a second control means for selectively controlling operation of either of said pair of fluid pressure actuators, and means Yoperative when said one uid pressure actuator and one of said pair of fluid pressure actuators are in operation, upon operation of said second control means to terminate operation of the operated one of said pair and operation of the other of said pair, to prevent such operation of the other of said pair except in response to operation of said first control means to terminate operation of said one fluid pressure actuator.

6. In combination with a source of fluid under pressure, a first control pipe, second and third control pipes, first fluid pressure actuator means operated by supply of fluid under pressure to said first control pipe, second and third means operated in response to supply of fluid under pressure to said second and third control pipes, respectively, a fluid pressure supply pipe, control means operable to either of two positions to establish connection between said supply pipe and either of said control pipes, respectively, while venting the other of said control pipes, rst relay valve means responsive to supply and release, respectively, of iluid under pressure to and from a first control chamber to establish either a first fluid pressure communication between said supply pipe and atmosphere or a second fluid pressure communication between said supply pipe and said source, second relay valve means responsive to supply and release, respectively, of fluid under pressure to and from a second control chamber when another chamber is void of fluid under pressure to establish either a third fluid pressure communication between said first control chamber and atmosphere or a fourth fluid pressure communication between said control chamber and said rst control pipe and responsive to supply of fluid under pressure to said other chamber to establish said fourth communication, shuttle valve means having opposite inlet openings connected to said second and third control pipes, respectively, and an outlet opening connected to said second control chamber, and inverse double check valve means operable in response to pressurization of both of said control pipes to effect supply of fluid under pressure from one of said control pipes to said other chamber and, when either or both of said control pipes are vented, to effect venting of said other chamber.

'7. The combination as set forth ln claim 6, including check valve and choke means in said fourth communication to allow for facile ow of fluid under pressure from said rst control pipe to said first control chamber and restricted flow in the opposite direction.

8. The combination as set forth in claim 6, including fluid storing means in said fourth communication.

9. A control mechanism for one actuator and a -v pair of actuators, comprising a source of fluid .7, tion of either one of said pair of actuators to render said first interlock means non-responsive to pressurization of said one actuator, and third interlock means responsive to pressurization of both of said pair of actuators to render said second interlock means ineffective and said first interlock means therefore effective.

ROY R. STEVENS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,286,873 Schwartz June 16, 1942 2,464,986 Miller Mar. 22, 1949 

